1. Field of the Invention
The present invention relates to a process for synthesizing a large amount of spinel type silicon nitride powders of a high-pressure phase, which has been unknown so far. The present invention particularly relates to a process for synthesizing spinel type silicon nitride powders by converting silicon nitride of a law pressure phase to the one of a high pressure phase with shock wave compression treatment.
2. Description of the Prior Art
A synthesizing process of spinel type silicon nitride powders have been a process of reacting Si with N2 fluid in a diamond anvil cell, or a process of pressing and heating silicon nitride powders of low pressure phase such as α-Si3N4, β-Si3N4 or amorphous Si3N4 at 15 GPa or more and 2000 K or more.
In the above-mentioned conventional processes, however, the amount of spinel type silicon nitride powders that can be synthesized at a time is usually about 50 ng that is very slight. It was therefore difficult to obtain a sufficient amount of spinel type silicon nitride powders for their industrial applications or evaluation of their properties.